在 python 2.7 中使用 PI

Question

I am trying to access the value of pi in Python 2.7, but it seems as if Python doesn't recognize math.pi. I am using IDLE, and when I try to print the value of math.pi, it says that "Math is not defined" or "math is not defined". I can't upgrade to the next version without risk, so is there a way to access pi in Python 2.7? Alternatively, is there another way to convert degrees to radians in Python 2.7 without dealing with Pi?

Answer 1

Python 2.7.5 (default, May 15 2013, 22:44:16) [MSC v.1500 64 bit (AMD64)] on win32
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>>> import math
>>> math.pi
3.141592653589793

Check out the Python tutorial on modules and how to use them.

As for the second part of your question, Python comes with batteries included , of course:

>>> math.radians(90)
1.5707963267948966
>>> math.radians(180)
3.141592653589793

Answer 2

To have access to stuff provided by math module, like pi . You need to import the module first:

import math
print (math.pi)